


The Doctor And His Patient

by Lawfuless



Category: Undertale (Video Game)
Genre: Alternate Universe - Canon Divergence, Character Death, Minor Character Death, Original Character Death(s), Post-Undertale Neutral Route - Exiled Queen Ending, Self-Sacrifice, Soul Bond
Language: English
Status: Completed
Published: 2017-01-29
Updated: 2017-01-29
Packaged: 2018-09-20 15:28:43
Rating: General Audiences
Warnings: Major Character Death
Chapters: 1
Words: 1,382
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/9498362
Author URL: https://archiveofourown.org/users/Lawfuless/pseuds/Lawfuless
Summary: The human had a white soul. He claimed it was due to an alignment towards order. Magi tended towards Order or Chaos, characterized by black or white souls. He wished he could quiz Kent more, but the human was sickly, and needed sleep. He ran scans and came up with the same conclusion each time-- The child was dying. When asked, the boy nodded. "I have been for awhile... That's why I came here. To help undo this mess. With my soul, you can break free. Collect the other six souls and destroy the barrier... That's what you want, isn't it?" Sans shook his head, but he wasn't the only one in the room.Once he left, the other made themselves visible for a flickering moment. "You would help us?" it asked. He nodded, then brought forth his soul. The creature slowly came forward, cupping the soul. When Sans returned, it was to a bright, blinding light. He shielded his eyelights, waiting. Then he carefully removed his arm. There was one figure standing in the center of the room. The blond turned, eyes a solid black save for the white pinpricks in the center. Black scars ran down their face and Sans froze. "Hello son."After a neutral run, a new human falls down... Things don't go as planned.





	

**Author's Note:**

> Based a lot off http://legapandora.deviantart.com/art/undertale-w-d-gaster-584543891 This amazing picture by legapandora.  
> Basically, I got bored and felt like doing a thing.

He had heard the thump from the next room. He quirked his head before heading into the large room. He already spotted the lump of fabric in the pile of flowers. But he waited a moment to make sure it was alive. Slowly, the human pushed itself up and dusted itself off, looking around before up. "...He's so going to kill me." The human said aloud, wincing and rubbing his head. Then he looked over at the doorway where Sans waited. He cupped his hands, bringing his soul out to cast a bright white light. It lit up his blond hair until it was a shimmering silver, grey-blue eyes turning a solid white. He headed forwards, only pausing a brief moment as he passed Sans.

The youth headed through the darkness until he reached the ruins and tucked away his soul, stopping to lean on a wall, coughing hard. He then wiped red from his lips, staining part of his white robes crimson. "Gods be damned, this isn't the boon he made it out to be." The human rubbed his chest, gritting blood-stained teeth. He tried to straighten and move on, but he quickly collapsed. Nearby monsters drifted away, concerned. Sans finally let out a sigh and came over, extending a hand.

"Hey pal... Don't you know when to ask for help? Take my hand." He winced at the faintly tight grip forcing his bones to rub against each other but he grinned and beared it. He pulled him up and patted the other's back. "You don't look so good, kiddo. Could use a rest. How's about we go to my place? I know a short-cut." He barely waited for the other to give a cautious nod before he was bringing them to his place. He snapped and took them to his house, helping him onto his bed, tucking him in. The other drifted off almost immediately.

Over time, he regained enough strength to talk and move around. He introduced himself as Kent, and explained he was a Magi. Like the kind that had locked his kind up. He did, however, admit that his family was a splinter group that had disagreed with most magi things. They hadn't wanted to lock up the monsters, they didn't believe Magi should remain separate from humans even when the humans had turned on them- after all, they had magic in common with monster- and had managed to keep their abilities as a result. It did, however, mean that they were often watched over. He himself had a guardian in the form of his father who had been attempting to train him on the mountain to see if the air would make it easier on him. Instead he had fallen into the underground.

The human had a white soul. He claimed it was due to an alignment towards order. Magi tended towards Order or Chaos, characterized by black or white souls. He wished he could quiz Kent more, but the human was sickly, and needed sleep. He ran scans and came up with the same conclusion each time-- The child was dying. When asked, the boy nodded. "I have been for awhile... That's why I came here. To help undo this mess. With my soul, you can break free. Collect the other six souls and destroy the barrier... That's what you want, isn't it?" Sans shook his head, but he wasn't the only one in the room.

Once he left, the other made themselves visible for a flickering moment. "You would help us?" it asked. He nodded, then brought forth his soul. The creature slowly came forward, cupping the soul. When Sans returned, it was to a bright, blinding light. He shielded his eyelights, waiting. Then he carefully removed his arm. There was one figure standing in the center of the room. The blond turned, eyes a solid black save for the white pinpricks in the center. Black scars ran down their face and Sans froze. "Hello son."

"Gaster? But how--" Sans cut himself off, shaking his head. "You... You used the human? Why? Why them?" he demanded. The other sighed, shaking his head, then patted the bed as he himself sat down and waited patiently to be joined before he said anything. Sans glared, but finally gave in and sat beside him, hunching over a bit.

"He was in the process of dying. He knew that. He offered his soul to help us. If I wanted to return... I needed a better link. You wouldn't accept his soul, and he knew it would just shatter if it was left outside of his body. We would lose our chance. So I took the offer. Two birds with one stone, so the human saying goes. I gained the link, and he got his wish... But more than that, he lives on." He tapped his chest. "You can see, can't you?" His soul was glowing a soft lavender, the colour of perseverance. He would continue, would persist even when faced with death.

San rubbed his jaw. "So... You two are... sharing?" He asked, but Gaster looked away. "No... He's not really there, is he? ...You're the one in control, and he takes a backseat to watch." his eyelights narrowed. "G, you takin' over someone else's life isn't fair, even if they let you. They deserve to live as much as you do." he jab a finger at the soul. "That? That's not what it's supposed to be."

Gaster sighed, bowing his head. "You're right. It is wrong. But I can't... I can't let go of the control. He... He's weak. Hardly able to hold himself together." Then he carefully held the heart better so the lavender was more visible as lines wrapping around the white soul. "We'd fall apart if I wasn't holding us together." He admitted softly. "Between the sickness and the void... we're falling apart slowly. ...We just... we need to save us. Break us free. Then... then we can rest." he looked up with dim eyelights. "Let us give you the freedom you deserve."

Sans looked at him, the lights of his eyes vanishing. "..." Then they lit up, aimed at the floor. "Alright. I'll get you to the barrier." He stood up and offered his hand. The other took it and stood, looking down at him with a sad smile. They shifted to the hallway the barrier contained. Slowly, Gaster released his hand and moved onwards alone. He went to the barrier and pressed his hands to it, soul pulled out. It pulsed, and the lavender vanished as he drew their magic out and forced it into the barrier. There was a loud whining as it strained against the combined magic before it cracked. Gaster stepped back, soul beginning to separate. He dropped to his knees and Sans teleported to his side.

They watched as the barrier shattered before them. A gentle smile came across his features as he leaned against Sans. "...Take care... of your brother..." His eyes slid shut and then his heart broke into pieces. What was left of his form dissolved into magic, dust and bones. Sans sat there for awhile before finally standing and heading back. Already monsters were gathering, hearing the shattering sound ringing through the underground. They looked to him with such hope, but paused when they noticed the dust. He walked past them, not caring. Once out of view, he made the jump through space to his house.

Papyrus was outside, waiting for him. "THERE YOU ARE LAZY BONES!" he cried, picking him up and hugging him tight. The shorter hugged him back just as tight. "...Are you alright, Sans?" he asked. Sans, choking up, nodded simply in reply. "Well, if you say you are, I have no choice but to believe you. Now, Undyne called to tell me to head to the castle! I figured we should get Toriel and head there together!"

"...Y-yeah. Let's do that. I'm certain she'd like that a lot..." Sans agreed, slowly releasing Papyrus. He wiped the remnants of tears from his eyesockets before his brother could see, straightening. ' _He'd want us to be happy._ ' he told himself, letting his grin widen. They would live on happily for his dad and the kid... They deserved that much for what they did.

**Author's Note:**

> That's all, folks.
> 
> To quickly answer any possible questions;  
> Q: Why did the barrier break?  
> A: It was reaaaallly old, faced against the magic of an ancient and pretty powerful skeleton combined with the human soul (a magi nonetheless) and the unholy powers of the void. It barely stood a chance.  
> Q: Why wasn't Kent's body left behind?  
> A: Due to Gaster not having a physical form, he took Kent's to use. However, due to the combination and the nature of Gaster, parts and things were missing which was why at the end he wasn't really a corpse. It was more magic that was keeping his human nature.  
> Q: How did Gaster even get back into the world?  
> A: After being in the void for so long, he was able to manipulate the code, which allowed the FUN values to change. He managed to alter the FUN value in Sans' room to act like the hallway in waterfall and made Sans' exit work like the grey door so it would trigger his appearance. As such, he was able to make himself appear so long as he didn't openly interact or allow the human to do much interacting with him.  
> Q: If this is a Neutral Route, who died?  
> A: Ten regular monsters. Therefore it was the Exiled Queen ending. Asgore is also dead.  
> Q: Don't you need a Boss Monster soul to combine with?  
> A: ...We don't know much about Gaster. Nor Boss Monsters, to my knowledge, so it is feasible that he became one. Or, at the very least, void-souls act funny. Seeing as the void is... void... it's empty, right? So, a void being would be empty inside. Or, their soul would be empty, allowing for something to fill it. Perhaps even a human soul. That could attribute to some of the instability, and why the soul immediately started to break apart. After all, you try pumping a bunch of water into a glass box. Like, try a lake into a 5" x 5" x 5" cube. I can assure you, somethings going to break.


End file.
